Effort-regulating manual control devices

ABSTRACT

A manual control device which permits adjusting with precision the raising mechanism of farm tractor implements, comprising two braked control members, namely an approach control member and an adjustment control member, each control member being rigid with pivot means connected through a link to an end pivot point of a lever of which the central point has pivoted thereon a control arm rigid with a rotary shaft.

United States Patent Rolland 5] Sept. 5, 1972 [5 EFFORT-REGULATING MANUAL [56] References Cited CONTROL DEVICES UNITED STATES PATENTS [721 Rolland, Billancoum France 1,825,577 9/1931 Carr ..74/479 73 Assignee; Regie Nationale Des Usims Renault, 3,451,286 6/1969 Bloom ..74/479 Billanco rt, H t France u e de Seme Primary Examiner-M1lton Kaufman Assistant Examiner-Ronald C. Capossela Flled! 1970 Attorney-Stevens, Davis, Miller & Mosher 21 A 1. No.: 92,480 1 PP [57] ABSTRACT A manual control device which pemiits adjusting with [30] Forelgn Application Pnonty Data precision the raising mechanism of farm tractor imple- Dec. 18, 1969 France ..6943919 mems, comprising two braked control r namely an approach control member and an adjust- 52] us. (:1 ..74/479, 74/522 'comrol member, each control member being 51 lm. Cl. ..G05g 11/00 rigid with Pivot mews thmugh a [58] Field of Search ..74/479, 522 end Pivot P0int a lever which cemral Pint has pivoted thereon a control arm rigid with a rotary shaft.

7 Claims, 5 Drawing Figures PATENTEDSEP 5:912

SHEET 1 [IF 3 PAIENTED P i n I 8.888.588

SHEET 2 BF 3 EFFORT-REGULATING MANUAL CONTROL DEVICES The present invention relates to a manual control device adapted to adjust the tractive effort regulating system of an implement raising mechanism, notably on farming tractors.

As a rule, tractors and other handling equipment comprise hydraulic means for raising implements which incorporates or has associated therewith a tractive effort regulator. This regulator is responsive to the variations in the reaction exerted by the ground on the implement being operated, by raising and lowering same in order to maintain a substantially constant tractive effort.

Raising mechanisms are already known wherein the angular stroke of a rotary shaft is utilized for actuating the tractive effort adjustment system. Now in many instances a direct control of this shaft by means of a manual lever is extremely inaccurate in that it is not capable of maintaining at a strict value the working depth of the implement.

To avoid this inconvenience relatively long hand levers have been used for producing long linear strokes at the lever end. However also in this case the proper position of the lever is obtained by manual feel, the adjustment precision being detrimentally affected during the operation of the tractor, or when the driver is exposed to sudden jolts.

It is an essential object of the present invention to provide a manual control for a rotary shaft and to angularly position this shaft by using a pair of control levers not rigidly connected to this shaft.

This manual control device comprising two control members having pivot means interconnected by a lever, is characterized essentially in that said lever interconnecting pivot pins each rigid with one of the two brake control members comprises three aligned pivot points of which the two end ones are rigid with a link pivoted on each one of said two control members, respectively, the central point having pivotally mounted thereon an operating arm rigid with the rotary shaft to be positioned.

With the control device thus constructed the control shaft can be actuated by means of the two members consisting of the approach or coarse positioning lever which the driver can quickly position in what he considers to be the most favorable zone, and an adjustment lever having its movement stepped-down, this adjustment lever being adapted to be actuated from the position in which the approach lever was previously set.

A clearer understanding of this invention will be gained from the following detailed description of a typical embodiment of the control device thereof which is given by way of example with reference to the attached drawings, in which:

FIG. 1 is a front elevational view of the device;

FIG. 2 is a side elevational view of the same device with a fragmentary section taken along the line II-II of FIG. 1, the shaft being partially removed;

FIG. 3 is a diagram corresponding to the mechanism of FIG. 1;

FIG. 4 is the modified diagram of the mechanism obtained from the construction of FIG. 3, after actuating and setting the approach lever, and

FIG. 5 is a modified diagram of the mechanism obtained from the construction of FIG. 3, after actuating the adjustment lever.

Referring to FIGS. 1 and 2 of the drawings it will be seen that the rotary shaft 1 to be positioned carries at its knurled end a bent lever arm 2 rigid with said shaft, due to the provision of a screw 3 interconnecting the two knurled arms 4, 4a of said arm, in order to clamp them against the corresponding knurled surface of shaft 1.

The arm 2 carries at its end a pivot such as a pin 5 having fulcrumed thereon a lever 6 provided at either end with ball joints i.e. a lower ball joint 7 and an upper ball joint 8, providing two other pivot points.

A link 9 having one end rigid with the lower ball joint 7 connects the latter to a control member referred to hereinafter as the adjustment lever 10 which comprises a ball joint 11 engaging the opposite end of link 9.

Similarly, the upper ball joint 8 of lever 6 is rigid with another link 12 connected through a pivot pin 13 to another control member 14 referred to herein as the approach lever.

A pair of studs 15 rigid with the case 16 carry two sets of clamping flanges 17 separated from each other by friction disks 18 between which the central portions of control members 10 and 14 are disposed. A pair of prestressed compression-springs 19 are disposed concentiically on said studs 15 and urge said sets of flanges 17 away from each other. The function of these springs is to brake the levers 10 and 14 by means of friction disks 18. The face 20 of case 16 and the adjacent first flange l7 constitute reaction surfaces permitting the simultaneous clamping of levers 10 and 14 urged by said springs 19.

The flanges 17 are force fitted on sockets 21 centered on a protection tube 22 surrounding the shaft 1.

This device operates as follows:

When the driver desires to adjust the sensitivity of the tractive effort control system to obtain a predetermined working depth, and assuming that the levers are initially positioned as shown in FIG. 3, he operates as follows:

1. First, he moves the approach lever 14 from the position of FIG. 3 to the position 14' (FIG. 4) corresponding approximately to the desired adjustment.

In FIG. 4 it will be seen that this movement of lever 14 is attended by a proportional movement of bent lever 6 transmitted through ball joint 13, link 12 and ball joint 8. The pivot point 11 on lever 10 remains stationary and holds the ball joint 7 through the medium of link 9. The lever 6 bearing on this fixed point 7 is moved through its ball joint 8 and actuates the control arm 2 to which it is connected via pin 5. The new positions thus obtained for the various component elements of the device are shown in the diagram of FIG. 4 by the same reference numerals with a prime exponent 2. To obtain an accurate depth adjustment the driver then moves the adjustment lever 10 in one or the other direction as shown in FIG. 5. The control arm 2 is moved as explained in the preceding paragraph, with the difference that it is the pivot pin 13' that acts as a fixed point, the lever 6 being actuated via the ball joint 7.

In this last operation the movements of pivot points 5, 7 and 8 to 5", 7" and 8" respectively of links 9, 12

and lever 6 are such that the angular movement of the control arm 2 to position 2 is extremely stepped down in relation to the movement of adjustment lever 10. This is due to the fact that the distances from pivot pins 11 and 13 to the axis of rotation of shaft 1 are unequal, and that pivot pin 11 is substantially nearer to this axis than pivot pin 13. The new positions thus obtained for the various component elements of the device are designated by the same reference numerals in FIG. but with the double-prime exponent The stepped down transmission thus obtained affords a considerably higher degree of precision and ease in the adjustment of the desired working depth.

Of course, various modifications and variations may be brought to the specific form of embodiment given herein by way of example as will readily occur to those skilled in the art, provided that said modifications and variations remain within the range of equivalence of the invention as set forth in the appended claims.

What is claimed as new is:

1. A device for controlling a rotatable shaft, comprisa rotatable shaft having a control arm rigidly attached to and extending generally radially from said shaft;

two control members separate from but rotatably mounted substantially coaxially with said shaft, and extending generally radially from said shaft;

means for braking the rotation of said control members about the axis of said shaft;

a lever having its central point of rotation pivotally mounted to said control arm at a distance along said control arm from said shaft;

one end of said lever pivotally connected to a first linkage member which is also pivotally connected to a first one of said control members at a distance along said first control member from said shaft; and

the second end of said lever pivotally connected to a second linkage member which is also pivotally connected to the second of said control members at a distance along said second control member from said shaft.

2. The device of claim 1, wherein said control members are mounted on axially diiferent sides of said control arm.

3. The device of claim 1, wherein the ends of said control members furtherest from said shaft comprise handles suitable for grasping with the human hand.

4. The device of claim 1, wherein said means for braking the rotation of said control members comprises friction discs and resilient means biasing said discs against said control members.

5. The device of claim 4, wherein said friction disks comprise a set of friction discs cooperating with each of said control members, and said resilient means comprises a compression spring located between said sets of friction discs.

6. The device of claim 1, wherein the distance from said shaft to the points at which said linkage members are pivotally connected to said control members, are unequal.

7. The device of claim 6, wherein said first control member is an approach member, and the second control member is an ad'ustment member, the point of attachment of the 1m age member to said ad ustment member being substantially nearer to said shaft than the point of attachment of the linkage member to said approach member. 

1. A device for controlling a rotatable shaft, comprising: a rotatable shaft having a control arm rigidly attached to and extending generally radially from said shaft; two control members separate from but rotatably mounted substantially coaxially with said shaft, and extending generally radially from said shaft; means for braking the rotation of said control members about the axis of said shaft; a lever having its central point of rotation pivotally mounted to said control arm at a distance along said control arm from said shaft; one end of said lever pivotally connected to a first linkage member which is also pivotally connected to a first one of said control members at a distance along said first control member from said shaft; and the second end of said lever pivotally connected to a second linkage member which is also pivotally connected to the second of said control members at a distance along said second control member from said shaft.
 2. The device of claim 1, wherein said control members are mounted on axially different sides of said control arm.
 3. The device of claim 1, wherein the ends of said control members furtherest from said shaft comprise handles suitable for grasping with the human hand.
 4. The device of claim 1, wherein said means for braking the rotation of said control members comprises friction discs and resilient means biasing said discs against said control members.
 5. The device of claim 4, wherein said friction disks comprise a set of friction discs cooperating with each of said control members, and said resilient means comprises a compression spring located between said sets of friction discs.
 6. The device of claim 1, wherein the distance from said shaft to the points at which said linkage members are pivotally connected to said control members, are unequal.
 7. The device of claim 6, wherein said first control member is an approach member, and the second control member is an adjustment member, the point of attachment of the linkage member to said adjustment member being substantially nearer to said shaft than the point of attachment of the linkage member to said approach member. 